System of coal homogenization on the coal stock piles is very effective from the point of view of running costs and eficiency. Coal homogenization can make an integral part of the quality management system in coal mines, as well as a strategy of processing for coal supplied by more suppliers in power stations and heat plants.
There are two possibilities of coal quality regulation on the coal stockpiles:
- homogenization at stockpile entry – storing in the whole area of the stock pile or its sector to ensure its constant and known quality. This can be reached by continuous layering coal of different quality on pre-defined places (according to amount and quality of coal stored and layered before) aiming at optimum quality within the location.
- homogenization at stockpile exit – it is ensured by taking coal by two or more machines from stockpile locations with known qualitative parameters according to previous measurements during coal storing on the stock pile. The desired quality is reached by mixing coal of different quality and verifying the parameters. Homogenization at the stockpile exit is a less effective way of homogenization, but it is possible to perform it with relatively simple technical equipment.
On-line radiometric coal ash analysers can be located on conveyor belts (in the area of coal stock pile) before the coal enters the stockpile to determine quality of new coal; then they can be located on coal stockpile machinery to detect real amount and quality of coal being layered to the given location and then at the exit of the stockpile to verify efficiency and accuracy of the homogenization.